View Full Version : Using POLYFIL in light loads

August 14, 2010, 04:24 PM
Hey yall, I came across some videos on youtube about using POLY-FIL (craft stuffing) in lightly charged cartridges. It makes sense that it holds the powder down at the flash hole in order to get a more consistent burn from one round to the next. I love the concept, but I have a few questions that maybe you guys have the answers to. How exactly would you determine the amount (in Grains) of Poly-Fil to use in any given cartridge? I would assume that it doesn't take much, but how much is too much? It does take up casing volume so it has to affect pressure to some degree, right? So, if it does affect pressures in the casing do I need to throw a lighter charge to accomodate for the extra space being taken up in case? I am not a competition shooter and my reloads to date are light loads for recreational plinking, but I do enjoy a good accurate round. It would seem that adding the Poly-Fil would increase accuaracy. I guess that I need to experiment and decide if I want to implement this into my normal routine. I've only been reloading for about a year now, so while this concept is new to me, perhaps some of you have some experience with this or something similar? Tell me what ya think guys! I put the links down here, you may have to cut and paste them, sorry. I shoot better than I run a computer:D


August 15, 2010, 12:48 PM
Stuff just enuff to hold the powder where ya want it (powder is lite , so not too much (packin) is required)

Then pull it back out & weigh it .

August 15, 2010, 01:05 PM
I wouldn't do it. I'd worry about it getting stuck in the gas system. Carbon and scale are bad enough without having to wory about melted polymers sticking to the gas system.

I'm not sure what this has to do with bullet casting. Am I missing something?

August 15, 2010, 03:26 PM
GP thanks for your input - 11B, yea man, I was looking at some posts in CASTING area and obviously didn't back out to the RELOADING area before posting the thread, WHOOPS! I promise it'll never happen again...........until next time;)

August 19, 2010, 08:28 AM
I'm not sure what this has to do with bullet casting. Am I missing something?

Yes & No,some people use POLY-FIL in cast bullet loads to take up the excess space and position the powder up agents the primer for more reliable ignition especially with large capacity cases.

You don't have to worry about the POLY-FIL leaving any residue in your bore or gas system,it's toast as soon as you pull the trigger. Personally I've never had to use it for any of my loads,the powders I use like 2400,Red Dot,IMR-4756 from my cast bullet loads are not case capacity or position sensitive and have worked well with the calibers I use them in.

James at Ammosmith has so very good videos as well as Eric/IV888.

August 22, 2010, 02:26 PM
I don't think your post is too bad out of place Lyman lists alot of loads for 45-70 and such large capacity cases with filler and their cast bullets.I have read about some such loads but have yet to try any.I have also read that some folks use cotton balls as it will burn away and not leave any obstruction in the barrel.

August 29, 2010, 02:38 PM
Hi there!

I used to shoot cast bullets (quite successfully) at 200 yards with the 30-06 and then the .308 using the Lyman 3111466 and the 311467 with the Dacron filler. The filler material is the same that you are referring to - it is used for stuffing. I used approximately 1/2 grain and tamped it down onto the charge of 4831. I stopped weighing the tufts after it was discovered that there was no discernible difference between weighing and not weighing. So I merely got used to pulling a tuft and stuffing down onto the powder charge. You will know when you have too much - there will be fine white filaments ejecting from the barrel. It is actually kinda neat to see it happen! :) All of the Dacron will be consumed when you have just the right amount. Of course this will all depend on the ingredients of your load.

I hope that this will help you.

September 27, 2010, 08:15 AM
If you reduce load very much, you run the risk of multiple ignition or "flash over" which can create excessive pressure. It dosnt happen very often, but it can happen. Its best to keep the powder as close to the primer as possible. Most manuals will give you a starting load. If you are loading below their starting load, then a filler would be a good idea.

October 2, 2010, 10:46 AM
Filler is one of the things that can make shooting interesting. It's one more thing to experiment on.
Those that shoot to "hear the noise" are missing a lot. When you handload, there are more options. I started loading when I was 12yo and told my mom that I was doing it to save money so I could shoot more... now at 63yo I shoot so I can load more, lol.
IMHO, the first video, loading .357 with Clays, is a total waste of time. It prolly won't hurt anything, but has no value. Clays, and similar fast powders, in small cases, and the .357 is a small case in the scheme of things, do not have any difficulty igniting, so the position of the powder won't affect anything. You can load more ammo by not inserting something that doesn't DO anything.
In the second video, ammosmith's, he's using an '06 and Unique. There MAY be some need there. There's a MUCH larger case, and very little more powder. I personally don't think it's that necessary, but think it would be a good idea for you to try it out on your own, to prove it one way or the other.
When I was MUCH younger, I read a lot of Townsend Whelen, and he was a hunter. He liked and had the opportunity to hunt all over the western hemisphere with just what was on his back. A pack, and a rifle had to last him the 3-days to a month that he was in the field. Depending on where he was, and how long he was gone, he would vary the gear. In Panama,ie he carried a Springfield, military issue, and some of his own handloads. Whenever he carried a large rifle, he'd carry a few "mid-range" that were loaded with either "pulled" fmjs, or cast. Then the powder would be pistol powder loaded to the 1200-1800fps range. The idea was to live off the land to some extent, and at 25-50yds he'd attempt to decapitate a bird(no, we're nor talking wren...)or small mammal. That became MY goal when I buy and shoot a "new" rifle, or some pistols. It just adds to the shooting, whether I ever actually do it or not. Whenever I go into the field, I drop a couple of those "mid-range" shells into my pocket.
In the larger rifles, the shells may be carried for several years, off and on, before being used. MOST have a filler, I use Polifil also, but there are several products. The point being, will powder migrate around the filler? (The answer...prolly not)
The tests you need to try are....How much accuracy do you get from the load? Is there an improvement/decrease with the filler? Is there a pressure difference with the filler? Are some powders more sensitive than others? All of these questions are to be answered by YOU.
The loads you'll start with are so low, you'll not be in danger. IOW, 12-15gr of Unique in an '06-.270 etc are going to be in the 10K range in a rifle that is made to be used in the 60K range. Pay attention, and don't stick a bullet. It's a pain to get out, but not dangerous IF YOU DON'T FIRE ANOTHER ROUND BEHIND IT!!!
I shoot ALL my tests over the chronograph, and have for over 30years, as they are tests. All information is appreciated, and the more at any given time, the better I like it.
The calibers I've tested are .300Savage, .308Winchester, .30/30, .30/06, .300WinMag, .25/35 Improved, a wildcat similar to the .250Savage Improved, .257Bob, .375/348 Improved, and .222. The powders vary from Bullseye, to 4895(both of them)
Have fun,

October 3, 2010, 07:42 AM
I experimented with using polyester fill and cast lead rifle bullets some years ago. Had some incidents of rust in the bore when I neglected to clean promptly. Discussing using polyester as a filler with a chemist, he advised that one of products of combustion of polyester was water. I stopped doing it and found accuracy without fillers. Most of my rifles (except a 38-55), shot best with Rx7 powder and no fillers.

October 4, 2010, 10:24 AM

Water is also one of the combustion products of smokeless powder. It is for anything that burns which has hydrogen and oxygen in it, such as nitrated cellulose or glycerin. It should exit as vapor, considering the temperatures powder burns at. Something else was responsible there.

October 5, 2010, 08:11 AM
I use it sometimes. No problems at all and no complaints. Makes me feel better with light charges when the powder is locked against the primer. My cast 243's shoot 3/4" at 100yds so why screw with it.

October 23, 2010, 12:57 PM
What if a circle of cardboard was used to reduce case volume? Seems like it would work. ( powder charge, insert the circle then bullet. )

10 Spot Terminator
October 30, 2010, 09:00 AM

Not sure if you are ready for this one but here goes anyway. I had been mulling over the problem of powder positioning in cases with very small powder charges for years. It started after reading an article 15 years or so back where a long time match shooter stated for best results with his low charge loads he would before firing each round, point his muzzle skyward and gently shake his pistol then ever so slowly lower the muzzle to point of aim and fire for most consistant performance. To me this wasnt saying there was a solution rather than telling me there was a problem. I started dabbling with ideas what to stuff into the cases that would hold the powder level and pressed securely against the bottom of the case and not harm me or the gun. I knew I wanted something that would burn quickly and hopefully before it hit the barrel . I looked into flash paper but found it to be highly unstable capable of ignition under minor every day situations which might set the rounds off on their own. Not so good , didnt go there. I then started checking different types of paper that I might cut some wads out of but when found those that burned the quickest they were too soft and lofty to make wads out of or to get into the cases straight so I pretty much gave up on the idea of making wads. Then one day day while on domestic KP I was pulling towels out of the drier and when I cleaned that fluffy sheet of poof from the lint screen it hit me. Cotton ! The wonder fabric ! Well I dropped the towels, grabbed a book of matches and a table spoon, pulled off a piece of that lint, touced a match to it and "WHOOF" it was gone and this little tiny ball of ash about the size of a piece of #2 shot floated into the air. Tired of writing , you figure out the rest ,,,;)


October 30, 2010, 09:23 AM
Good point, 10 Spot. Dryer lint is in some circles highly regarded as a fire starter.
I don't agree with the need for filler. The .38 target load is why: it contains less than 3 grains of dense, fast-burning powder in a rather large space. Even when HBWC's are used there is still plenty of room for the primer's spark to travel over the powder charge. My stock 586 is capable of shooting groups of slighly over an inch @ 50 yds with these loads. I've personally fired over 100k of these rounds, have been in attendance when many times that were fired. Never seen a "flashover kaboom". Last I heard no one has been able to recreate one under controlled conditions.